Method for producing polyalkenyl succinimide products, novel polyalkenylsuccinimide products with improved properties, intermediate products

ABSTRACT

A process for the preparation of polyalkenylsuccinimide products, in particular polyisobutenylsuccinimide products, is proposed, in which a polyalkene is reacted with a maleic acid, maleic anhydride or a functional derivative thereof to give a polyalkenylsuccinic anhydride and the polyalkenylsuccinic anhydride is then reacted with an oligoamine or polyamine, the polyalkenylsuccinic anhydride either
     (a) first being reacted with an alcohol or phenol and, without isolation of the reaction product, then with the oligoamine or polyamine, or   (b) the polyalkenylsuccinic anhydride being reacted with the oligoamine or polyamine in the presence of an alcohol or phenol and   (c) if desired, the alcohol or the phenol then being removed.   

     Novel polyalkenylsuccinimide products, in particular polyisobutenylsuccinimide products, and fuel additives are also proposed.

Method for producing polyalkenyl succinimide products, novel polyalkenylsuccinimide products with improved properties, intermediate products andthe use thereof

The present invention relates to a process for the preparation ofpolyalkenylsuccinimide products, in particular polyisobutenylsuccinimideproducts, novel polyalkenylsuccinimide products, in particularpolyisobutenylsuccinimide products, having improved properties,polyisobutenylsuccinic monoester intermediates and their use in thenovel process for the preparation of polyisobutenylsuccinimide products,a process for the preparation of the intermediates, and the use of thepolyalkenylsuccinimide products, in particular polyisobutenylsuccinimideproducts, as additives for fuels or lubricants.

The preparation of polyalkenylsuccinimide, for example apolyisobutenylsuccinimide, from a polyolefin, e.g. polyisobutene, andmaleic anhydride with formation of a polyalkenylsuccinic anhydride, e.g.a polyisobutenylsuccinic anhydride, and subsequent imidation isdescribed in the prior art, cf. for example EP-A-264247 or EP-A-271937.Thus, EP-A-264247 describes, on page 4, the reaction of maleic anhydridewith an olefinic polymer, for example polyisobutene, by heating in anene reaction with formation of a polyisobutenylsuccinic anhydride, whichcan then be reacted with a polyamine to give the correspondingpolyisobutenylsuccinimide (cf. also example 1 of the publication).

EP-A-271937 describes the preparation of polyolefin-substitutedsuccinimides, in particular of polyisobutene-substituted succinimides.Here, the polyalkene or halogenated polyalkene is reacted with maleicanhydride at from 140 to 220° C., preferably in the presence ofchlorine, and the resulting product is then reacted with the polyamine.

The reactions described in the prior art are generally carried outaccording to the following reaction scheme, shown forpolyisobutenylsuccinimide by way of example.

Reaction Scheme:

Synthesis of polyisobutenylsuccinimide (PIBSI) according to the priorart, EP-A-264247

The polyalkenylsuccinimides described in the prior art are widely used,usually in combination with other additives, in fuels and lubricants,cf. for example EP-A-264247, pages 8/9, EP-A-271937 and WO 98/42808 tomention but a few examples.

Thus, WO 98/42808 describes the use of a reaction product of apolyalkenyl derivative of a monoethylenically unsaturatedC₄-C₁₀-dicarboxylic acid with a polyamine as a dispersant additive forlow-sulfur diesel fuels. These may be reaction products ofpolyisobutenylsuccinic anhydride and polyamines.

EP-A-839840 proposes succinimide compounds obtained from a succinic acidprovided with an alkenyl or alkyl group as a side chain, or thecorresponding anhydride, and a polyamine. These compounds are said toact as lubricant additives and counteract corrosion of diesel fuelshaving a high sulfur content. The side chain may be, for example, apolyisobutene. The reaction of the acid component with the polyaminetakes place in a molar ratio of acid component to polyamine of 2.0 ormore.

The succinimide compounds are characterized by two infrared absorptionbands, an α-peak at 1640±10 cm⁻¹ and a β-peak at 1700±10 cm⁻¹, with anα-peak:β-peak intensity ratio of 0.12 or more. Since it is known, forexample, that the position of the infrared absorption band and inparticular the relative intensities are highly dependent on themeasuring conditions, and the publication makes no mention of this, itis not possible to determine the products in this publication.

The literature also describes the preparation ofpolyalkenylsuccinimides, for example polyisobutylsuccinimides, andother, aftertreated additives for lubricating oils and fuels, startingfrom olefins and unsaturated acid components, for example maleicanhydride, or functional acid derivatives in which the radicals locatedat the carbonyl function may be OH, Cl or O-lower alkyl (cf.EP-A-657475). However, this publication clearly concentrates on the useof the anhydride, especially since all examples describe the use ofmaleic anhydride in the reaction with the polyolefin.

The same applies to EP-A-441014 and EP-A-587331, in which the examplesare likewise restricted to the use of maleic anhydride.

None of the publications specifically mentions monoesters ofpolyisobutenylsuccinic acid.

U.S. Pat. No. 5,279,626 describes fuel additives which may containreaction products of polyamines with hydrocarbyl-substituted succinicacid acylating agents. These include, the anhydrides, acid halides andesters (column 5). No mention is made of monoesters in the publication.However, U.S. Pat. No. 5,279,626 (cf. column 6) recommends theadditional use of corrosion inhibitors, including monoesters ofalkenylsuccinic acids having 8 to 24 carbon atoms in the alkenyl groupwith alcohols, such as polyglycols.

In the course of the present invention, it was found that, in thepreparation of polyalkenylsuccinimides, in particular ofpolyisobutenylsuccinimide, a considerable volume increase unexpectedlyoccurs in the reactor during the stage in which polyalkenylsuccinicanhydride, in particular polyisobutenylsuccinic anhydride, is reactedwith an oligoamine or polyamine. This is based, on the one hand, on theelimination of water or steam and, on the other hand, on an evidentlylarge intermediate viscosity increase, which occurs when thepolyalkenylsuccinic anhydride, in particular polyisobutenylsuccinicanhydride, is combined with the oligoamine or polyamine component. Thisvolume increase is the limiting factor in determining the batch size inan existing plant. According to the Applicant's observation based onthis phenomenon, the plant can as a rule be filled to only 60% of thetheoretical capacity. This means that, in order to achieve specificbatch sizes, production plants are required which, owing to the frothingof the mixture of starting materials, have to have a substantiallylarger capacity than would be required without the occurrence of thefrothing phenomenon.

It is an object of the present invention to improve the known processfor the preparation of a polyalkenylsuccinimide, in particular apolyisobutenylsuccinimide, by reacting a polyolefin, i.e. polyisobutene,with maleic acid, maleic anhydride or the functional derivatives thereofto give a polyalkenylsuccinic anhydride, in particular apolyisobutenylsuccinic anhydride, and then reacting thepolyalkenylsuccinic anhydride, in particular polyisobutenylsuccinicanhydride, with an oligoamine or polyamine, so that the frothing of themixture of starting materials comprising polyalkenylsuccinic anhydride,in particular polyisobutenylsuccinic anhydride, and the oligoamine orpolyamine is prevented or at least greatly reduced. It is clear that thepolyolefin used in the preparation of the polyalkenylsuccinanhydride hasterminal double bonds, in particular double bonds of a vinylidenestructure, which may undergo an ene-reaction together with the maleicacid anhydride. The amount of terminal double bonds in the polyolefinis, thus, in general at least 50 mol % and in particular at least 75 mol% (as determined with ¹H-NMR spectroscopy and if desired in combinationwith ¹³C-NMR spectroscopy in a known manner).

We have found that this object is achieved by a process of said type,wherein a polyalkenylsuccinic anhydride, in particular apolyisobutenylsuccinic anhydride, is either

-   (a) first reacted with an alcohol or phenol and, without isolation    of the reaction product, then with the oligoamine or polyamine, or-   (b) the polyalkenylsuccinic anhydride, in particular    polyisobutenylsuccinic anhydride, is reacted with the oligoamine or    polyamine in the presence of an alcohol or phenol and-   (c) if desired, the alcohol or the phenol is then removed.

Surprisingly, there is no frothing of the mixture of the startingmaterials in the novel process, so that, for the same batch, it ispossible to manage with reactor volumes which are substantially smallerthan those required to date. According to the novel process, the degreeof filling of a plant can be increased to 85% or more of the maximumcapacity, depending on the chosen reaction temperature. This improvesthe cost-efficiency of the process in the long term.

The novel process is further explained below with reference to thepreferred embodiment using a polyisobutenylsuccinic anhydride, as anexample for a polyalkenylsuccinimide. The data given forpolyisobutenylsuccinanhydride correspond to otherpolyalkenylsuccinanhydrides.

The novel process comprises two variants: either the resultingpolyisobutenylsuccinic anhydride is first reacted with the alcohol orphenol and the reaction product, without isolation, i.e. in situ orimmediately, is then reacted with the oligoamine or polyamine. This canbe effected in such a way that the polyisobutenylsuccinic anhydride isbrought into contact with the alcohol or phenol, the reaction is allowedto take place and the oligoamine or polyamine is then introduced intothe reaction space. Isolation of the monoester formed as an intermediateis not necessary. Alternatively, the polyisobutenylsuccinic anhydridecan be reacted with the oligoamine or polyamine in the presence of thealcohol or phenol.

After the reaction, the alcohol or the phenol can, if desired, beremoved in a conventional manner. However, this is not essential and canalso advantageously be dispensed with.

The reaction of the polyisobutenylsuccinic anhydride with the alcohol orphenol is expediently effected at elevated temperatures, preferably atfrom 50 to 180° C., in particular from 80 to 160° C.

The novel process not only surprisingly solves the problem of frothingof the mixture of starting materials. The resultingpolyalkenylsuccinimide products also differ in their properties from thepolyalkenylsuccinimides of the prior art. The relatively large amount ofcorresponding amides always obtained in the known prior art processes issubstantially reduced. In addition, the novel polyalkenylsuccinimideproducts contain no ester fractions, although the reaction with thealcohol or phenol was carried out in an intermediate stage.

The polyalkenylsuccinimide products and in particular the novelpolyisobutenylsuccinimides obtained according to the invention, not onlyhave a different composition to the polyisobutenylsuccinimides of theprior art but also surprisingly have superior properties compared withthe known products. For example, the dispersant effect is substantiallyimproved. When they are used in fuel, this is evident from a lowerdegree of coking of the injection/burner nozzles. The substantialimprovement in the dispersant effect is also found when the novelpolyalkenylsuccinimide products, in particular thepolyisobutenylsuccinimide products, are used as additives forlubricants. Furthermore, the novel polyalkenylsuccinimide products, inparticular the polyisobutenylsuccinimide products, are particularlyeffective for protection from corrosion and wear.

Accordingly, the present invention furthermore relates to the provisionof novel polyalkenylsuccinimide products, in particular thepolyisobutenylsuccinimide products, having superior properties.

The novel polyalkenylsuccinimide products, in particular thepolyisobutenylsuccinimide products, are obtainable by a process in whicha polyolefin, particularly a polyisobutene having terminal double bonds,is reacted with maleic acid, maleic anhydride or a functional derivativethereof to give a polyalkenylsuccinic anhydride, and thepolyalkenylsuccinic anhydride or a functional derivative thereof is thenreacted with an oligoamine or polyamine, polyalkenylsuccinic anhydrideor its functional derivative either

-   (a) first being reacted with an alcohol or phenol and then, without    isolation of the reaction product, with the oligoamine or polyamine,    or-   (b) the polyalkenylsuccinic anhydride or its functional derivative    is reacted with the oligoamine or polyamine in the presence of an    alcohol or phenol and-   (c) if desired, the alcohol or the phenol is then removed.

The novel polyalkenylsuccinimide products obtained from apolyalkenylsuccinic anhydride or a functional derivative thereof and anoligoamine or polyamine contain not more than 30% by weight, based onthe total weight of the product mixture, of the correspondingpolyalkenylsuccinamide or polyalkenylsuccinic acid monoamide.Preferably, the amount of the corresponding polyalkenylsuccinamide ormonoamide is not more than 25% by weight, based on the total weight ofthe product.

The quantitative determination of the amount of polyalkenylsuccinamideor polyalkenylsuccinic acid monoamide or polyalkenylsuccinimide in thenovel product is carried out by the IR method explained below:

A quantitative determination of imide and amide substituents in thenovel polyalkenyl derivative can be effected, for example, on the basisof the IR bands. With the chosen apparatus and under the chosenexperimental conditions, these are at 1703 cm⁻¹ (imide) and 1666 cm⁻¹(amide), and the reference band for polyisobutylene is at 1367 cm⁻¹.

The spectrometer used was a Nicolet Magna 550 (measuring parameter:resolution 4 cm⁻¹). The sample was applied as a thin film on a KBrwindow for the measurement.

Evaluation:

The determination of the extinction (band height) at the abovementionedwave numbers is carried out with the aid of a baseline with referencepoints 1807 cm⁻¹ and 1045 cm⁻¹. By calculating the quotient extinction(1666 cm⁻¹)/extinction (1703 cm⁻¹), it is possible to specify only arelative amide/imide ratio since the amide and imide bands at the sameconcentration do not have the same intensity (different oscillatorstrength or excitation probability of imide and amide vibration).

On the basis of two samples having different imide/amide ratios, it ispossible, by spectral subtraction, to obtain spectra which containeither-only the imide or the amide band plus the isobutylene groupsassociated with the substituent. The 2nd spectrum is weighted in such away that the band of the respective other substituent is compensated(zero line). This gives an artificial polyisobutylene (PIB)-amide orPIB-imide spectrum. Any free unsubstituted PIB fractions contained inthe sample result in additional absorptions at the PIB reference band at1367 cm⁻¹ in these artificial spectra. If, for example, the imidespectrum thus obtained (plus said free PIB groups) is subtracted from an“original” sample spectrum, this only contains the vibration band whichbelong to the amide-substituted PIB. In order to obtain the spectralcomponent of the imide-substituted PIB, the artificial PIB-amidespectrum must accordingly be subtracted from the sample spectrum.

In the spectral components thus obtained for the imide- oramide-substituted PIB, the ratiosR1=extinction (amide band)/extinction (polyisobutylene)andR2=extinction (imide band)/extinction (polyisobutylene)can now be determined by evaluating the band. As a result of thesynthesis, both the amide-substituted and imide-substituted PIB have thesame chain length (20 isobutylene units) so that, on standardization ofthe amide-substituted and imide-substituted PIB spectra to the 1367 cm⁻¹band, the extinction ratio E(1703 cm⁻¹)/E(1666 cm⁻¹) gives the factor bywhich the imide group is more intense than the amide group when detectedby IR spectroscopy. The same is obtained computationally if R2 isdivided by R1.

On the basis of representative samples, this (detection) factor wasdetermined as F(I/A)=1.23. This value means that, at the sameconcentration, the imide band is about 23% higher than the amide band.If the relative amide/imide ratio mentioned at the outset is multipliedby this factor, the absolute ratio of these two functional groups in thesample to be analyzed is obtained:Amide/imide ratio=R=1.23*extinction (1666 cm⁻¹)/extinction (1703cm⁻¹)  (1)

From the amide/imide ratio R=A/I according to formula (I), it is nowpossible to calculate the respective amide and imide content:The following is true A+I=1  (2)From (1) and (2)

A+A/R=1

A(1+1/V)=1amide content A=R/(1+R)  (3)andimide content I=R/(1+R)  (4)

TABLE I Determination of the amide secondary component Ratio of AmideRatio of PIBSA/ content* Alcohol PIBSA¹⁾/ROH Amine amine [%] Batch 1 — —TETA²⁾ 1.0 40.4 Batch 2 — — TEPA³⁾ 1.0 37.2 Batch 3 n-Butanol 0.5 TEPA1.0 27.3 Batch 4 2-Ethylhexanol 1 TEPA 1.0 21.0 Batch 5 Isopropanol 1TETA 1.0 24.1 Batch 6 2-Ethylhexanol 0.5 TETA 1.0 16.8 *According toabove IR spectroscopic method ¹⁾PIBSA = Polyisobutyleneamine ²⁾TETA =Tetraethylenepentamine ³⁾TEPA = Triethylenepentamine

Particularly preferred novel polyisobutenylsuccinimide products arethose obtained from

-   (i) polyisobutene having a number average molecular weight M_(n) of    from 500 to 10000 Dalton and a content of terminal double bonds of    more than 50, preferably more than 75, mol %-   (ii) maleic anhydride and-   (iii) a linear, branched, cyclic or cyclic branched    alkylenepolyamine having 1 to 10 carbon atoms in each alkylene group    and 2 to 12 nitrogen atoms, of which at least one nitrogen atom is    present as a primary amino group, or mixtures thereof,    containing not more than 30% by weight, based on the total weight of    the product, of the corresponding polyisobutenylsuccinamide.

Very particularly preferred novel polyisobutenylsuccinimide products arethose obtained from

-   (i) polyisobutene having a number average molecular weight M_(n) of    from 500 to 10000 Dalton and a content of terminal double bonds of    more than 50, preferably more than 75, mol %,-   (ii) maleic anhydride and-   (iii) an oligoamine or polyamine of the formula I:    H₂N(CH₂)_(x)—NH—[(CH₂)_(y)—NH]_(z)—(CH₂)_(x)NH₂  (I),    -   where _(x) and _(y), independently of one another, are each an        integer from 1 to 5, preferably from 2 to 4, and _(z) is an        integer from 0 to 8.

The present invention also relates to novel polyisobutenylsuccinic acidmonoester intermediates obtained from

-   (i) polyisobutene having a number average molecular weight M_(n) of    from 500 to 10000 Dalton and a content of terminal double bonds of    more than 50, preferably more than 75, mol %,-   (ii) maleic anhydride and-   (iii) alcohols of the formula ROH, where R is straight-chain or    branched, cyclic or branched cyclic alkyl of 1 to 16 carbon atoms,    or phenols.

The novel polyisobutenylsuccinic acid monoester intermediates occur inthe novel process for the preparation of polyisobutenylsuccinimideproducts and can, if desired, also be isolated. They are not only usefulintermediates but, alone or in combination with other additives, canalso be used as additives for fuels or lubricants.

The present invention furthermore relates to a process for thepreparation of polyisobutenylsuccinic acid monoester intermediates, inwhich a polyisobutene having terminal double bonds or whose content ofterminal double bonds is at least 50 mol %, particularly at least 75 mol%, is reacted with the maleic acid, maleic anhydride or a functionalderivative thereof, wherein the resulting polyisobutenylsuccinicanhydride is reacted with the alcohol.

The present invention also relates to the use of thepolyisobutenylsuccinic acid monoester intermediates in the novel processfor the preparation of polyisobutenylsuccinimide products.

Finally, the present invention relates to the use of the novelpolyisobutenylsuccinimide products as additives for fuels, in particulardiesel fuels, kerosine or middle distillates generally, heating oil andgasoline fuel, or lubricants.

According to the invention, diesel fuel additive mixtures, gasoline fueladditives and lubricant compositions are also provided, each of whichcontains an effective amount of novel polyisobutenylsuccinimideproducts.

The novel process is explained in more detail below.

For the preparation of the polyolefin-succinic anhydride, in particularpolyisobutenylsuccinic anhydride (PIBSA), in the first stage, it isexpedient to start from a polyolefin (polyalkene), for examplepolyisobutene, and a monounsaturated acid, the corresponding anhydrideor ester, preferably maleic anhydride. In an ene reaction, thepolyolefin undergoes an addition at the double bond of the acidcomponent.

A particularly suitable polyolefin is polyisobutene (PIB).Polyisobutenes are described in the prior art. For example, DE-A-4319672describes a process for the preparation of polyisobutenylsuccinicanhydride for polyisobutene and maleic anhydride, in which polyisobutenecontaining at least 50% of terminal double bonds is reacted with excessmaleic anhydride at from 140 to 200° C.

In principle, polyisobutenes having a very broad number averagemolecular weight M_(n) of from 350 to 20000 Dalton can be used in thenovel process.

Polyolefins, in particular polyisobutenes, having a number averagemolecular weight range (M_(n)) of from 500 to 10000, preferably from 500to 5000, are particularly preferred. Polyisobutenes of this molecularweight range are prepared, for example, according to U.S. Pat. No.5,137,980, EP-A-145235 or U.S. Pat. No. 5,068,490. Oligopropenes orpolypropenes can preferably be obtained via metallocene catalysis andare described, for example, in EP-A-490454. Oligoolefins and polyolefinsof the butenes, pentenes, hexenes and decenes and copolymers of olefinmixtures which may also contain up to 70 mol % of ethylene, are also ofparticular interest. The homo- and copolymers of the 1-olefins viametallocene catalysis are also particularly preferred.

Polyolefins having high contents of terminal vinyl or vinylidene doublebonds, i.e. those which have more than 50 mol %, preferably more than 70mol %, of terminal double bonds, are preferred. The dispersity D(M_(w)/M_(n)) of the polymers used is preferably less than 3. Narrowdistributions are preferred. Dispersity is understood as meaning thequotient of the weight average molecular weight M_(w) divided by thenumber average molecular weight M_(n). For example, polyisobutene havingdistributions of less than 2.0 for ≦M_(n) 2000 and less than 1.5 for≦M_(n) 1000 are particularly advantageous. The polyolefin should be freeof organic and inorganic bases, water, alcohols, ethers, acids andperoxides.

Particularly suitable polyisobutenes are in particular highly reactivepolyisobutenes which have a high content of terminal ethylenic doublebonds. Suitable highly reactive polyisobutenes are, for example,polyisobutenes which contain >70, in particular >80, especially >85, mol% of vinylidene double bonds. Polyisobutenes which have uniform polymerbackbones are particularly preferred. Uniform polymer backbones arepossessed in particular by those polyisobutenes which are composed of atleast 85, preferably at least 90, particularly preferably at least 95, %by weight of isobutene units. Such highly reactive polyisobutenespreferably have a number average molecular weight M_(n) of from 350 to20000 Dalton. The highly reactive polyisobutenes can have apolydispersity of <2.5, for example <1.5 at M_(n)≦1000.

Particularly suitable highly reactive polyisobutenes are, for example,the Glissopal® grades from BASF Atiengesellschaft, in particularGlissopal 1000 (M_(n)=1000), Glissopal 550 (V 33 (M_(n)=550)) andGlissopal 2300 (M_(n)=2300) and mixtures thereof. Other number averagemolecular weights can be established in a manner known in principle, bymixing polyisobutenes of different number average molecular weights orby extractive enrichment of polyisobutenes of specific molecular weightranges.

In novel processes, the polyolefin, in particular polyisobutene can bereacted with maleic acid, maleic anhydride or a functional derivativethereof to give a polyisobutenylsuccinamide. The term functionalderivative is understood as meaning those derivatives which lead to thesame or a comparable result or product. In the case of maleic acid,functional derivatives include, for example, monoalkyl maleates, dialkylmaleates, maleyl dichloride, maleyl dibromide, maleic acid monoalkylester monochloride or maleic acid monoalkyl ester monobromide. Thealcohol components used in the case of the maleates are, for example,lower alkyl radicals of, for example, 1 to 6, in particular 1 to 4,carbon atoms, for example methyl or ethyl.

The polyisobutenylsuccinic anhydride formed as an intermediate in thenovel process may also be present in the form of a functionalderivative, for example in the form of a free acid, of a lower alkylmono- or diester, or of an acid halide (chloride or bromide). The loweralkyl radical in the ester derivative may comprise, for example, 1 to 6carbon atoms.

Oligoamines or polyamines are used in the novel process. These may be,for example, alkylenepolyamines, including methylenepolyamines,ethylenepolyamines, butylenepolyamines, propylenepolyamines andpentylenepolyamines. Specific examples of such polyamines includeethylenediamine, triethylenetetramine, propylenediamine,trimethylenediamine, tripropylenetetramine, tetraethylenepentamine,hexaethyleneheptamine, pentaethylenehexamine and mixtures thereof.

Such polyamines are described in detail in the chapter Ethylene Aminesin Kirk Othmer's Encyclopedia of Chemical Technology, 2nd Edition,Volume 7, pages 22-37, Interscience Publishers, New York (1965). Suchpolyamines are particularly expediently prepared by reacting ethylenedichloride with ammonia or by reacting an ethyleneimine with aring-opening agent, for example water or ammonia.

Particularly preferred oligoamines or polyamines in the novel processare of the structural formula I:H₂N(CH₂)_(x)—NH—[(CH₂)_(y)—NH]_(z)—(CH₂)_(x)NH₂  (I),where _(x) and _(y), independently of one another, are each an integerfrom 1 to 5, preferably from 2 to 4, and _(z) is an integer from 0 to 8,or mixtures thereof.

The alcohols which can be used in the novel process are preferablymonohydric alcohols, but polyhydric alcohols are also suitable.

Monohydric or polyhydric alcohols of 1 to 16 carbon atoms areparticularly preferred.

Suitable alcohols include methanol, ethanol, n-propanol, isopropanol,cyclopropylcarbinol, n-butanol, sec-butanol, isobutanol, tert-butanol,2-hydroxymethylfuran, amyl alcohol, isoamyl alcohol, vinylcarbinol,cyclohexanol, n-hexanol, 4-methyl-2-pentanol, 2-ethylbutyl alcohol,sec-capryl alcohol, 2-ethylhexanol, n-decanol, lauryl alcohol, isocetylalcohol and mixtures thereof. Preferred alcohols are those of 6 to 16carbon atoms, 2-ethylhexanol being particularly preferred.

The molar ratio of the polyalkenylsuccinic anhydride, in particularpolyisobutenylsuccinic anhydride, to alcohol may vary within a widerange. It is not necessary to use stoichiometric amounts of alcohol, andeven comparatively small molar amounts of alcohol are sufficient toachieve the advantageous effect of the novel process. An expedient molarPIBSA:alcohol ratio is from 10 to 0.5, preferably from 4 to 0.8.

The phenols include phenol, naphthol, (o,p)-alkylphenols, e.g.di-tert-butylphenol, and salicylic acid.

The novel process for the preparation of novel polyisobutenylsuccinimideproducts can be controlled in a suitable manner so that a larger amountof either monosuccinimides or bissuccinimides is formed. The novelpolyisobutenylsuccinimide products having a higher monosuccinimidecontent are particularly suitable as additives for fuels (diesel fuel,heating oil, gasoline fuel), while the novel polyisobutenylsuccinimideproducts having a higher content of bissuccinimides are particularlysuitable as additives for lubricants. The ratio of monoimides tobisimides formed can be influenced, for example, by the molar ratio ofpolyisobutenylsuccinic anhydride to oligoamine or polyamine. The largerthe molar amount of polyisobutenylsuccinic anhydride in relation to theoligoamine or polyamine, the larger the resulting amounts of novelmonosuccinimide, and vice versa.

In order to obtain a high proportion of monosuccinimide, a molar(PIBSA):oligoamine or polyamine ratio of from 0.7 to 1.3, particularlypreferably from 0.9 to 1.1, is employed.

In order to obtain a higher proportion of bissuccinimide, a molarPIBSA:oligoamine or polyamine ratio of from 3 to 18, particularlypreferably from 2.3 to 1.9, is preferably employed.

The novel polyisobutenylsuccinimide products can be used as additives(additive packets) for fuels, in particular diesel fuel, heating oil,kerosine or middle distillates generally and gasoline fuel, orlubricants.

If the novel polyisobutenylsuccinimide products are used as diesel fueladditives, they contain an effective amount of polyisobutenylsuccinimideproducts. The diesel fuel additives expediently contain from 10 to 5000ppm, preferably from 50 to 1000 ppm, based on the total weight of thediesel fuel, of polyisobutenylsuccinimide products.

The diesel fuel additive mixtures contain at least one further additiveselected from detergents, lubricity additives, corrosion inhibitors,cetane number improvers, demulsifiers, antifoams, solvents,solubilizers, antioxidants, metal deactivators, deodorants and other,conventional additives.

The novel polyisobutenylsuccinimide products can also be used asadditives for heating oil. They are used in an effective amount,expediently in an amount of from 10 to 1000 ppm, preferably from 50 to500 ppm, based on the total weight of the heating oil. This may containat least one further additive which may be selected from corrosioninhibitors, demulsifiers, antifoams antioxidants, metal deactivators,ferrocenes and deodorants.

The novel polyisobutenylsuccinimide products can also be used forgasoline fuel additive mixtures. These contain an effective amount ofnovel polyisobutenylsuccinimide products, expediently from 10 to 5000ppm, preferably from 50 to 2000 ppm, based on the total weight of thegasoline fuel.

The gasoline fuel additive mixture containing novelpolyisobutenylsuccinimide products may also contain at least one furtheradditive selected from detergent additives, carrier oils, lubricityadditives, solvents and corrosion inhibitors.

Finally, the novel polyisobutenylsuccinimide products are also suitablefor lubricant compositions, which contain an effective amount of novelproducts, expediently from 0.1 to 10, preferably from 0.5 to 5, % byweight, based on the total weight of the lubricant composition.

The lubricant composition containing novel polyisobutenylsuccinimideproducts can also contain further additives which are selected inparticular from lubricity additives, antiwear additives, corrosioninhibitors and viscosity index improvers.

The novel polyalkenylsuccinimide products are particularly preferablycombined with at least one fuel additive, in particular gasoline fueladditive, having a detergent action or inhibiting valve seat wear action(referred to below as detergent additive). This detergent additive hasat least one hydrophobic hydrocarbon-radical having a number averagemolecular weight (M_(n)) of from 85 to 20000 and at least one polargroup selected from:

-   -   (a) mono- or polyamino groups of up to 6 nitrogen atoms, at        least one nitrogen atom having basic properties;    -   (b) nitro groups, if required in combination with hydroxyl        groups;    -   (c) hydroxyl groups in combination with mono- or polyamino        groups, at least one nitrogen atom having basic properties;    -   (d) carboxyl groups or their alkali metal or alkaline earth        metal salts;    -   (e) sulfo groups or their alkali metal or alkaline earth metal        salts;    -   (f) polyoxy-C₂- to C₄-alkylene groups which are terminated by        hydroxyl groups or mono- or polyamino groups, at least one        nitrogen atom having basic properties, or by carbamate groups;    -   (g) carboxylic ester groups;    -   (h) groups derived from succinic anhydride and having hydroxyl        and/or amino and/or amido and/or imido groups; and    -   (i) groups produced by Mannich reaction of substituted phenols        with aldehydes and mono- or polyamines.

The hydrophobic hydrocarbon radical in the above detergent additives,which ensures sufficient solubility in the fuel, has a number averagemolecular weight (M_(n)) of from 85 to 20000, in particular from 113 to10000, especially from 300 to 5000. Typical hydrophobic hydrocarbonradicals, in particular in combination with polar groups (a), (c), (h)and (i), are the polypropenyl, polybutenyl and polyisobutenyl radicals,each having an M_(n) of from 300 to 5000, in particular from 500 to2500, especially from 700 to 2300.

Examples of the above groups of detergent additives are the following:

Additives containing mono- or polyamino groups (a) are preferablypolyalkenmono- or polyalkenpolyamines based on polypropene or on highlyreactive (i.e. having predominantly terminal double bonds—generally inthe alpha- and beta-position) or conventional (i.e. having predominantlymiddle double bonds) polybutene or polyisobutene having an M_(n) of from300 to 5000. Such additives based on highly reactive polyisobutenes,which can be prepared from the polyisobutene, which may contain up to20% by weight of n-butene units, by hydroformylation and reductiveamination with ammonia, monoamines or polyamines, such asdimethylaminopropylamine, ethylenediamine, diethylenetriamine,triethylenetetramine or tetraethylenepentamine, are disclosed inparticular in EP-A-244 616. If, in the preparation of the additives,polybutene or polyisobutene having predominantly middle double bonds(generally in the beta- and gamma-position) is used as a startingmaterial, preparation by chlorination and subsequent amination or byoxidation of the double bond with air or ozone to give the carbonyl orcarboxyl compound and subsequent amination under reductive(hydrogenating) conditions is possible. The amines used here for theamination may be the same as those used above for the reductiveamination of the hydroformylated highly reactive polyisobutene.Corresponding additives based on polypropene are described in particularin WO-A-94/24231.

Further preferred additives containing monoamino groups (a) are thehydrogenation products of the reaction products of polyisobutene havingan average degree of polymerization P of from 5 to 100 with oxides ofnitrogen or mixtures of oxides of nitrogen and oxygen, as described inparticular in WO-A-97/03946.

Further preferred additives containing monoamino groups (a) are thecompounds obtainable from polyisobutene epoxides by reaction with aminesand subsequent dehydration and reduction of the aminoalcohols, asdescribed in particular in DE-A-196 20 262.

Additives containing nitro groups, if required in combination withhydroxyl groups, (b) are preferably reaction products of polyisobuteneshaving an average degree of polymerization P of from 5 to 100 or from 10to 100 with oxides of nitrogen or mixtures of oxide of nitrogen andoxygen, as described in particular in WO-A-96/03367 and WO-A-96/03479.These reaction products are as a rule mixtures of purenitropolyisobutanes (e.g. 2,4-dinitropolyisobutane) and mixedhydroxynitropolyisobutanes (e.g. 2-nitro-4-hydroxypolyisobutane).

Additives containing hydroxyl groups in combination with mono- orpolyamino groups (c) are in particular reaction products ofpolyisobutene epoxides, obtainable from polyisobutene preferably havingpredominantly terminal double bonds and having an M_(n) of from 300 to5000, with ammonia or mono- or polyamines, as described in particular inEP-A-476 485.

Additives containing carboxyl groups or their alkali metal or alkalineearth metal salts (d) are preferably copolymers of C₂-C₄₀-olefins withmaleic anhydride, having a total molar mass of from 500 to 20000, someor all of the carboxyl groups of which have been converted into thealkali metal or alkaline earth metal salts and the remainder of thecarboxyl groups have been reacted with alcohols or amines. Suchadditives are disclosed in particular in EP-A-307 815. Such additivesserve mainly for preventing valve seat wear and, as described inWO-A-87/01126, can advantageously be used in combination withconventional fuel detergents, such as poly(iso)buteneamines orpolyetheramines.

Additives containing sulfo groups or their alkali metal or alkalineearth metal salts (e) are preferably alkali metal or alkaline earthmetal salts of an alkyl sulfosuccinate, as described in particular inEP-A-639 632. Such additives serve mainly for preventing valve seat wearand can advantageously be used in combination with conventional fueldetergents, such as poly(iso)buteneamines or polyetheramines.

Additives containing polyoxy-C₂-C₄-alkylene groups (f) are preferablypolyethers or polyetheramines, which are obtainable by reactingC₂-C₆₀-alkanols, C₆-C₃₀-alkanediols, mono- or di-C₂-C₃₀-alkylamines,C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenols with from 1 to 30 molof ethylene oxide and/or propylene oxide and/or butylene oxide perhydroxyl group or amino group and, in the case of the polyetheramines,by subsequent reductive amination by ammonia, monoamines or polyamines.Such products are described in particular in EP-A-310 875, EP-A-356 725,EP-A-700 985 and U.S. Pat. No. 4,877,416. In the case of polyethers,such products also have carrier oil properties, Typical examples ofthese are butoxylates of tridecanol and isotridecanol, isononylphenolbutoxylates and polyisobutenol butoxylates and propoxylates and thecorresponding reaction products with ammonia.

Additives containing carboxylic ester groups (g) are preferably estersof mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, in particular those having a minimum viscosity of 2 mm²/s at100° C., as described in particular in DE-A-38 38 918. Mono-, di- ortricarboxylic acids which may be used are aliphatic or aromatic acids,and suitable ester alcohols and polyols are in particular long-chainmembers of, for example, 6 to 24 carbon atoms. Typical members of theesters are adipates, phthalates, isophthalates, terephthalates andtrimellitates of isooctanol, of isononanol, of isodecanol and ofisotridecanol. Such products also have carrier oil properties.

Additives which contain groups derived from succinic anhydride andhaving hydroxyl and/or amino and/or amido and/or imido groups (h) arepreferably corresponding derivates of polyisobutenylsuccinic anhydridewhich are obtainable by reacting conventional or highly reactivepolyisobutene having an M_(n) of from 300 to 5000 with maleic anhydrideby a thermal route or via the chlorinated polyisobutene. Of particularinterest here are the derivatives with aliphatic polyamines, such asethylenediamine, diethylenetriamine, triethylenetetramine ortetraethylenepentamine. Such gasoline fuel additives are described inparticular in U.S. Pat. No. 4,849,572.

Additives containing groups produced by Mannich reaction of substitutedphenols with aldehydes and mono- or polyamines (i) are preferablyreaction products of polyisobutene-substituted phenols with formaldehydeand mono- or polyamines, such as ethylenediamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine ordimethylaminopropylamine. The polyisobutenyl-substituted phenol mayoriginate from conventional or highly reactive polyisobutene having anM_(n) of from 300 to 5000. Such polyisobutene Mannich-bases aredescribed in particular in EP-A-831 141.

With regard to a more exact definition of the individual gasoline fueladditives mentioned, the disclosures of the abovementioned publicationsof the prior art are hereby expressly incorporated by reference.

The novel fuel additive composition can moreover contain furtherconventional components and additives. Carrier oils without pronounceddetergent effect may primarily be mentioned here.

Suitable mineral carrier oils are fractions obtained in mineral oilprocessing, such as kerosine or naphtha, brightstock or base oils havingviscosities, for example, of grades SN 500-2000, as well as aromatichydrocarbons, paraffinic hydrocarbons and alkoxyalkanols. A fraction(vacuum distillate cut having a boiling range of about 360 to 500° C.,obtainable from natural mineral oil catalytically hydrogenated underhigh pressure and isomerized and deparaffinized) known as hydrocrack oiland obtained in the refining of mineral oils may also be used. Mixturesof the abovementioned mineral carrier oils are also suitable.

Examples of synthetic carrier oils which may be used according to theinvention are selected from: polyolefins (poly-alpha-olefins orpoly-internal-olefins), (poly)esters, (poly)alkoxylates, polyethers,aliphatic polyetheramines, alkylphenol-initiated polyethers,alkylphenol-initiated polyetheramines and carboxylic esters oflong-chain alkanols.

Examples of suitable polyolefins are olefin polymers having an M_(n) offrom 400 to 1800, especially based on polybutene or polyisobutene(hydrogenated or unhydrogenated).

Examples of suitable polyethers or polyetheramines are preferablycompounds which contain polyoxy-C₂-C₄-alkylene groups and which areobtainable by reaction of C₂-C₆₀-alkanols, C₆-C₃₀-alkanediols, mono- ordi-C₂-C₃₀-alkylamines, C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenolswith from 1 to 30 mol of ethylene oxide and/or propylene oxide and/orbutylene oxide per hydroxyl group or amino group and, in the case of thepolyetheramines, by subsequent reductive amination with ammonia,monoamines or polyamines. Such products are described in particular inEPA-310 875, EP-A-356 725, EP-A-700 985 and U.S. Pat. No. 4,877,416. Forexample, poly-C₂-C₆-alkylene oxide amines or functional derivativesthereof may be used as polyetheramines. Typical examples of these arebutoxylates of tridecanol and of isotridecanol, isononylphenolbutoxylates and polyisobutenol butoxylates and propoxylates and thecorresponding reaction products of ammonia.

Examples of carboxylic esters of long-chain alkanols are in particularesters of mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, as described in particular in DE-A-38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids, andsuitable ester alcohols and ester polyols are in particular long-chainmembers having, for example, 6 to 24 carbon atoms. Typical esters areadipates, phthalates, isophthalates, terephthalates and trimellitates ofisooctanol, of isononanol, of isodecanol and of isotridecanol, e.g.di(n-tridecyl or isotridecyl) phthalate.

Further suitable carrier oil systems are described, for example, inDE-A-38 26 608, DE-A-41 42 241, DE-A-43 09 074, EP-A-0 452 328 andEP-A-0 548 617, which are hereby expressly incorporated by reference.

Examples of particularly suitable synthetic carrier oils arealcohol-initiated polyethers having from about 5 to 35, e.g. from about5 to 30, C₃-C₆-alkylene oxide units, for example selected from propyleneoxide, n-butylene oxide and isobutylene oxide units, or mixturesthereof. Nonlimiting examples of suitable initiator alcohols arelong-chain alkanols or phenols substituted by long-chain alkyl, thelong-chain alkyl radical being in particular a straight-chain orbranched C₆-C₁₈-alkyl radical, preferably a C₈-C₁₅-alkyl radical.Preferred examples are tridecanol and nonylphenol.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, asdescribed in DE-A-101 02 913.6.

Further conventional additives are corrosion inhibitors, for examplebased on those ammonium salts of organic carboxylic acids which tend toform films or on heterocyclic aromatics in the corrosion protection ofnonferrous metals; antioxidants or stabilizers, for example based onamines, such as p-phenylenediamine, dicyclohexylamine or derivativesthereof or on phenols, such as 2,4-di-tert-butylphenol or3,5-di-tert-butyl-4-hydroxyphenylpropionic acid; demulsifiers;antistatic agents; metallocenes, such as ferrocene;methylcyclopentadienlylmanganesetricarbonyl; lubricity additives, suchas specific fatty acids, alkenylsuccinic esters, bis(hydroxyalkyl) fattyamines, hydroxyacetamides or castor oil; and markers. If required,amines may also be added for reducing the pH of the fuel.

The components or additives can be added to the fuel, e.g. gasolinefuel, individually or as a previously prepared concentrate (additivepacket), together with the novel polyalkenylsuccinimide.

Said detergent additives having the polar groups (a) to (i) are added tothe gasoline fuel usually in an amount of from 10 to 5000, in particularfrom 50 to 1000, ppm by weight. The other components and additivesmentioned are added, if desired, in amounts customary for this purpose.

The novel additive compositions can be used in all conventional gasolinefuels, as described, for example, in Ullmann's Encyclopedia ofIndustrial Chemistry, 5th Edition, 1990, Volume A16, page 719 et seq.

For example, the use in a gasoline fuel having an aromatics content ofnot more than 42% by volume and a sulfur content of not more than 150ppm by weight is possible.

The aromatics content of the gasoline fuel is, for example, from 30 to42, in particular from 32 to 40, % by volume.

The sulfur content of the gasoline fuel is, for example, from 5 to 150,in particular from 10 to 100, ppm by weight.

The gasoline fuel has, for example, an olefin content of from 6 to 21,in particular from 7 to 18, % by volume.

The gasoline fuel may have, for example, a benzene content of from 0.5to 1.0, in particular from 0.6 to 0.9, % by volume.

The gasoline fuel has, for example, an oxygen content of from 1.0 to2.7, in particular from 1.2 to 2.0, % by weight.

Gasoline fuels which may be particularly mentioned by way of example arethose which simultaneously have an aromatics content of not more than38% by volume, an olefin content of not more than 21% by volume, asulfur content of not more than 50 ppm by weight, a benzene content ofnot more than 1.0% by volume and an oxygen content of from 1.0 to 2.7%by weight.

The content of alcohols and ethers in the gasoline fuel is usuallyrelatively low. Typical maximum contents are 3% by volume for methanol,5% by volume for ethanol, 10% by volume for isopropanol, 7% by volume oftert-butanol, 10% by volume of isobutanol and 15% by volume for ethershaving 5 or more carbon atoms in the molecule.

The summer vapor pressure of the gasoline fuel is usually not more than70, in particular 60, kPa (in each case at 37° C.). The RON of thegasoline fuel is as a rule from 90 to 100. A usual range for thecorresponding MON is from 80 to 90.

Said specifications are determined by conventional methods (DIN EN 228).

The examples which follow illustrate the invention.

EXAMPLES 1 AND 2 Prevention of the Frothing of the Mixture of StartingMaterials

For determining the required reaction volume or the volume increaseduring the reaction, a graduated 500 ml reaction flask with a stirrerand a likewise graduated riser tube (capacity 200 ml) was filled with300 g of polyisobutenylsuccinic anhydride (PIBSA) (saponification valueSV 95) and 50 g of tetraethylenepentamine. After thorough mixing of thestarting materials, the total volume V₀ was determined as 375 ml, or alevel of 75%, at a temperature of 50° C. The content of the flask asthen heated to 140° C. within 20 minutes. The degree of filling of thevolume of starting materials was determined at intervals of 3 minutes(without a stirrer or with the stirrer switched off). The additives usedin each case (alcohol or solvent) are listed in the table below. In eachcase the maximum volume increase observed was used for the evaluation.

TABLE II ROH Solvent* V₀ V_(max.) ΔV [ml] [ml] [ml] [ml] [%] Comparison— — 375 640 71 Example 2 Ethylhexanol 40 — 415 460 10.8 Example 3n-Butanol 25 — 400 450 12.5 Comparison — 40 415 675 63 *Solvesso ® 150

Thus, the batch yield can be increased by about 40% by the noveladdition of alcohol in the case of a given reaction container. Thevolume increase still occurring in the presence of the alcohol can besubstantially ascribed to the thermal expansion of the reaction mixtureon heating to 140° C.

EXAMPLES 3 TO 7 Preparation of Monosuccinimides as Additives for Fuels

General Procedure:

In a 1 l three-necked flask, 630 g of polyisobutenylsuccinic anhydride(PIBSA) 1000 having a number average molecular weight M_(n) of 1000 anda saponification value of 95 are mixed with from 0.2 to 2 mol of analcohol (ROH) and heated to 80 to 160° C. in the course of 20-minutes.0.55 mol of an amine (for example 105 g of tetraethylenepentamine (TEPA)or 82 g of triethylenetetramine (TETA)) is added. At from 150 to 180°C., stirring is then continued for from 90 to 180 minutes. If desired,the alcohol can then be removed under reduced pressure.

For determining the saponification value, 1.0 g of product is refluxedin 25 ml of a 0.5 normal KOH with 1:1 ethanol/toluene as solvent for 10minutes, the hotplate is removed, the reflux condenser is washed with 20ml of methanol and, after cooling, back-titration is effected withaqueous HCl.

TABLE 1 Molar Molar PIBSA/ PIBSA/ ROH amine Example Alcohol ratio Amineratio 3 Ethanol 1.0 TEPA¹⁾ 1.0 4 n-Butanol 0.5 TEPA 1.0 5 2-Ethylhexanol1.0 TEPA 1.0 6 Isopropanol 1.0 TETA²⁾ 1.0 7 2-Ethylhexanol 0.5 TETA 1.0¹⁾TEPA: Tetraethylenepentamine ²⁾TETA: Triethylenetetramine

EXAMPLES 8 TO 11 Preparation of Bissuccinimides as Additives forLubricating Oils

General Procedure:

In a 1 l three-necked flask, 680 g of polyisobutenylsuccinic anhydride1000 having a number average molecular weight M_(n) of 1000 Dalton and asaponification value of 95 are mixed with from 0.2 to 2 mol of analcohol (ROH) and heated to 80 to 160° C. in the course of 20 minutes.0.3 mol of tetraethylenepentamine (TEPA) or triethylenetetramine (TETA)is added. At from 150 to 180° C., stirring is continued for from 90 to160 minutes. The product is then freed from the alcohol under reducedpressure.

The details are shown in table 2 below.

TABLE 2 Molar Molar PIBSA/ROH PIBSA/amine Example Alcohol ratio Amineratio 8 2-Ethylhexanol 1.5 TEPA¹⁾ 2.0 9 n-Butanol 1.0 TETA²⁾ 2.0 102-Ethylhexanol 1.0 TETA 2.0 11 2-Ethylhexanol 1.0 TETA 2.0 ¹⁾TEPA:Tetraethylenepentamine ²⁾TETA: TriethylenetetramineResults of the Engine Tests

Engine tests were carried out on a stationary Peugeot diesel engine typeXUD 9, 45 kW, 1.9 l stroke×bore). A low-sulfur diesel fuel according toEN 590, having a detergent content of 300 ppm, was used.

For the comparative example, 300 ppm of a commercial monosuccinimidedispersant were added to a commercial fuel corresponding to DK EN 590.The monosuccinimide dispersant was prepared by a process which wascarried out without the novel alcohol addition. PIBSA 1000 and TEPA wereused. This preparation process is described in WO 98/12282 andEP-A-271937, respectively.

A 6 hour cycle with variable speed and declining power output was chosenas the test procedure for determining engine deposits. The test wascarried out analogously to the methods described in the draft forEuropean standard CEC-PF 023. The cleanliness of the combustion chamberwas then quantitatively determined. Deposits on the injection nozzlewere determined from the reduction in the flow rate in % according toISO 4113.

TABLE 3 Comparative Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 example Deposits in525 370 380 530 405 560 combustion chamber [mg/cylinder] Reduced flow 5346 42 49 45 61 rate in injection nozzles [%] Results for performance oflubricating oil additives

The spot test is described, inter alia, in Les Huiles pour Moteurs et leGraissage des Moteurs, Volume 1, 1962, pages 89-90, by A. Schilling.

TABLE 4 Comparative Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 example* Results ofthe 615 638 653 605 623 580 Tupfel test *Prepared without addition ofalcohol by a process substantially described in DE-A-2808105 andUS-A-5,137,978.

1. A process for the preparation of a polyisobutenylsuccinimide product,comprising reacting a polyisobutene with maleic acid, maleic anhydrideor a functional derivative thereof to give a polyisobutenylsuccinicanhydride and then reacting the polyisobutenylsuccinic anhydride with anoligoamine or polyamine, wherein the polyisobutenylsuccinic anhydride iseither (a) first reacted with a C₁-C₁₆-alcohol or phenol and, withoutisolation of the reaction product, then with the oligoamine orpolyamine, and unreacted or cleaved alcohol, or unreacted or cleavedphenol, is then optionally removed, or (b) reacted with the oligoamineor polyamine in the presence of the alcohol or phenol as a reactant, andunreacted or cleaved alcohol, or unreacted or cleaved phenol, is thenoptionally removed, wherein the alcohol is selected from the groupconsisting of monohydric alcohols of the formula ROH, where R isstraight-chain or branched, cyclic or branched cyclic alkyl of 1 to 16carbon atoms.
 2. A process as claimed in claim 1, wherein the reactionwith the alcohol or phenol is carried out at elevated temperatures.
 3. Aprocess as claimed in claim 1, wherein the alcohol is used.
 4. A processas claimed in claim 1, wherein the oligoamines or polyamines used arethose of the formula I:H₂N(CH₂)_(x)—NH—[(CH₂)_(y)—NH]_(z)—(CH₂)_(x)NH₂  (I), where x and y,independently of one another, are each an integer from 1 to 5 and z isan integer from 0 to 8, or mixtures thereof.
 5. Apolyisobutenylsuccinimide product obtainable by a process comprisingreacting a polyisobutene with maleic acid, maleic anhydride or afunctional derivative thereof to give a polyisobutenylsuccinic anhydrideand then reacting the polyisobutenylsuccinic anhydride with anoligoamine or polyamine, the polyisobutenylsuccinic anhydride either (a)first reacted with a C₁-C₁₆-alcohol or phenol and, without isolation ofthe reaction product, then with the oligoamine or polyamine, andunreacted or cleaved alcohol, or unreacted or cleaved phenol, is thenoptionally removed, or (b) being reacted with the oligoamine orpolyamine in the presence of the alcohol or phenol as a reactant, andunreacted or cleaved alcohol, or unreacted or cleaved phenol, is thenoptionally removed, wherein the alcohol is selected from the groupconsisting of monohydric alcohols of the formula ROH, where R isstraight-chain or branched, cyclic or branched cyclic alkyl of 1 to 16carbon atoms.
 6. A polyisobutenylsuccinic monoester intermediateobtained by reaction of components comprising (a) polyisobutene having anumber average molecular weight Mn of from 500 to 10000 Dalton and acontent of terminal double bonds of more than 50 mol %, (b) maleicanhydride and (c) an alcohol of the formula ROH, where R isstraight-chain or branched, cyclic or branched cyclic alkyl of 1 to 16carbon atoms, or phenols.
 7. A polyisobutenylsuccinic monoesterintermediate as claimed in claim 6, wherein (c) is 2-ethylhexanol.
 8. Aprocess for the preparation of a polyisobutenylsuccinic monoesterintermediate as claimed in claim 6 comprising reacting polyisobutenewith maleic acid, maleic anhydride or a functional derivative thereof,wherein the polyisobutenylsuccinic anhydride formed is reacted with thealcohol.
 9. A diesel fuel additive mixture, comprising an effectiveamount of a polyisobutenylsuccinimide product as claimed in claim 5 and,optionally, at least one further additive.
 10. A diesel fuel additivemixture as claimed in claim 9, comprising at least one further additiveselected from detergents, lubricity additives, corrosion inhibitors,cetane number improvers, demulsifiers, antifoams, solvents,solubilizers, antioxidants, metal deactivators and deodorants.
 11. Agasoline fuel additive mixture, comprising an effective amount of apolyisobutenylsuccinimide product, as claimed in claim 5, and,optionally, at least one further additive.
 12. A gasoline fuel additivemixture as claimed in claim 11, comprising at least one further additiveselected from detergent additives, carrier oils, lubricity additives,solvents and corrosion inhibitors.
 13. A lubricant composition,comprising an effective amount of a polyisobutenylsuccinimide product asclaimed in claim 5, and, optionally, at least one further additive. 14.A lubricant composition as claimed in claim 13, comprising at least onefurther additive selected from lubricity additives, antiwear additives,corrosion inhibitors and viscosity index improvers/additives.
 15. Aprocess for the preparation of a polyisobutenylsuccinic monoesterintermediate as claimed in claim 7 comprising reacting polyisobutenewith maleic acid, maleic anhydride or a functional derivative thereof,wherein the polyisobutenylsuccinic anhydride formed is reacted with2-ethylhexanol.
 16. A process as claimed in claim 2, wherein thereaction is carried out at from 50 to 180° C.
 17. A process as claimedin claim 2, wherein the reaction is carried out at from 80 to 160° C.18. A polyisobutenylsuccinic monoester intermediate as claimed in claim6, wherein the polyisobutene has a content of terminal double bonds ofmore than 75 mol %.
 19. A polyisobutenylsuccinic monoester intermediateas claimed in claim 7, wherein the polyisobutene has a content ofterminal double bonds of more than 75 mol %.
 20. A process as claimed inclaim 1, wherein (a) is carried out.
 21. A process as claimed in claim1, wherein (b) is carried out.
 22. A polyisobutenylsuccinimide productas claimed in claim 5, wherein (a) is carried out.
 23. Apolyisobutenylsuccinimide product as claimed in claim 5, wherein (b) iscarried out.
 24. A diesel fuel comprising the diesel fuel additivemixture as claimed in claim
 9. 25. A gasoline fuel comprising thegasoline fuel additive mixture as claimed in claim 11.